001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.mapreduce;
020
021import java.io.IOException;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.mapreduce.InputFormat;
026import org.apache.hadoop.mapreduce.Mapper;
027import org.apache.hadoop.mapreduce.RecordReader;
028
029/**
030 * <code>InputSplit</code> represents the data to be processed by an 
031 * individual {@link Mapper}. 
032 *
033 * <p>Typically, it presents a byte-oriented view on the input and is the 
034 * responsibility of {@link RecordReader} of the job to process this and present
035 * a record-oriented view.
036 * 
037 * @see InputFormat
038 * @see RecordReader
039 */
040@InterfaceAudience.Public
041@InterfaceStability.Stable
042public abstract class InputSplit {
043  /**
044   * Get the size of the split, so that the input splits can be sorted by size.
045   * @return the number of bytes in the split
046   * @throws IOException
047   * @throws InterruptedException
048   */
049  public abstract long getLength() throws IOException, InterruptedException;
050
051  /**
052   * Get the list of nodes by name where the data for the split would be local.
053   * The locations do not need to be serialized.
054   * @return a new array of the node nodes.
055   * @throws IOException
056   * @throws InterruptedException
057   */
058  public abstract 
059    String[] getLocations() throws IOException, InterruptedException;
060}